1. Field
One or more aspects of embodiments according to the present invention relate to electronically scanned array antennas, and more particularly to an antenna capable of operating with multiple beams, and at multiple frequencies.
2. Description of Related Art
Electronically scanned array (ESA) antennas have multiple applications, including radar applications. In such applications, it may be desirable to transmit or receive more than one beam at a time, at more than one frequency, or with more than one polarization state. For example, it may be desirable for a system to be capable of operating both in the X band (8 GHz to 12 GHz) and in the Ku band (12 GHz to 18 GHz). While this can be accomplished using multiple separate antennas, the size, weight, and power (SWaP) of an assembly with multiple array antennas may be difficult to accommodate, e.g., on an aircraft.
One approach to achieving dual bands, or wideband ESAs, is to design the element spacing for the highest frequency band and let the lower frequency band also use the same element spacing. The problem with this approach is that the element spacing is not optimized for the lower frequency band SWaP. Another approach is to modulate each desired signal independently to achieve multiple independently modulated beams. This is not practical at X band and higher, however.
Thus, there is a need for a low-SWaP antenna system capable of transmitting and receiving more than one beam at a time, at more than one frequency, or with more than one polarization state.